Everywhere: Name debug macros more consistently.

Personally, I prefer the naming convention DEBUG_FOO over FOO_DEBUG, but
the majority of the debug macros are already named in the latter naming
convention, so I just enforce consistency here.

This was done with the following script:

    find . \( -name '*.cpp' -o -name '*.h' -o -name '*.in' \) -not -path './Toolchain/*' -not -path './Build/*' -exec sed -i -E 's/DEBUG_PATH/PATH_DEBUG/' {} \;

Userland/DevTools/UserspaceEmulator/Emulator.cpp

@@ -343,7 +343,7 @@ void Emulator::dump_backtrace()
 
 u32 Emulator::virt_syscall(u32 function, u32 arg1, u32 arg2, u32 arg3)
 {
-#if DEBUG_SPAM
+#if SPAM_DEBUG
     reportln("Syscall: {} ({:x})", Syscall::to_string((Syscall::Function)function), function);
 #endif
     switch (function) {